Variable speed drive control



Aug. 23, 1932. M. ZWICKY VARIABLE SPEED DRIVE CONTROL 2 Shets-Sheet Filed May 24, 1930 I 4 I NVENTOI k mz'arzw BY Fl Illa] AT'TORNEYS.

M. ZWICKY Aug. 23, 1932.

VARIABLE SPEED DRIVE CONTROL Filed May 24, 1930 2 Sheets-Sheet INVENTOR. zorZ wicfgr,

ATTORNEYS.

MELCHIOB'ZWICKY, OF BERKSHIRE HEIGHTS, PENNSYLVANIA, ASSIGNOR T TEXTILE v Patented Aug. 23, 1932 UNITED STATES PATENT OFFICE KACHM WORKS, OI WYOMISSING, PENNSYLVANIA. A CORPORATION OF PENN- S'YLVANIA VARIABLE SPEED DRIVE CONTROL Application filed May 24, 1930. Serial No. 455,197.

This invention relates generally to variable speed drive mechanisms incorporating a variable speed motor, and more specificallfy to one particularly adapted to straight or ull fashioned knitting machines.

It is well known that due to variations i ornamentation and reenforcing effects, yarns used, etc., certain parts of full fashioned stockings are producible at a higher machine speed than others. In order to expedite the production of such stockings, it is necessary to form the various parts thereof at the maximum speed at which perfect results are ob tainable. a

The variable s eed motor drive applied to these machines has been found to conveniently afford the necessary adjustability of speed for most efficient results; however, with this type of drive it has heretofore been possible for an unskilled or unreliable operator to run the machine at impropg speeds, with consequent detrimental effects in production.

The primary object of my invention is to provide a novel variable speed drive mechanism incorporating a variable speed motor which is normally operable at predetermined speeds only.

The lnventionv comprises the novel elements, features of construction and arrangement of parts in cooperative relationship as fully disclosed by the following detailed description and accompanying drawings of one embodiment thereof, reference to which will make the above and other objects, as

well as attendant advantages, .more readily ap arent.

In te accompanyin drawings Fig. 1 is a partia cross-sectional view through a full fashioned knitting machine having my improved variable speed motor drive applied thereto.

Fi 2, and 3 are enlarged fragmentar detai sectional views taken substantially as indicated by the arrows 2-2 and 33 on Fig. 1.

Fig. 4 is a cross-sectional view on the line 4- 4 of Fig. 2, partly broken away, and certain of the motor parts being omitted.

Fig. 5 is a fragmentary detail sectional view taken substantially as indicated by the arrows 5--5 on Fig. 2, but on a still larger scale.

Fig. 6 is a view similar to Fig. 5 but of a modified form of construction.

Figs. 7 and 8 are fragmentary sectionalindicated in dot-and-dash lines at 20 and which also carry suitable bearing supports for the sliafts, as well as other machine parts. Cam shaft 12 is commonly driven by the handwheel shaft through suitable connections therewith, (not shown) while the handwheel shaft is connected to a source of power, in the present instance a variable speed motor 15,

by a chain 16.

The variable speed motor illustrated is of the well known A. C. type in which the speed is changed by shifting the brushes 17 along its commutator segments 18. The brushes being connected toindependent phase windings on the stator. s 1

My invention is mainly directed to an improved speed controlling device in combination with such a'motor,,and to this end I employ brush shifting means operative upon the two segmental brush holder yokes 19 and 21,

(see Fig. 4) each of which has a pair of brushes 17 suitably mounted thereon for contact with the commutator segments 18, as usual. The yokes are movable toward and from each other along the commutator and are pivotally connected to projections on sep arate rotary disks 22 and 23, carried by and freely turnable on the motor shaft 24.

To simultaneously move the brushes, a common operating member 25 is provided which has a pin 26 fixed in its lower end loosely connecting with links 27 and 28 (see Figs.

5 and 7) in turn pivotally attached to the disks 22 and 23 respectively. The brush opera-ting member 25 is provided with a slot 29 near its lower end through which a pivot bolt 30 passes that is secured in the motor casing, as clearly shown in Fig. 2. A supporting plate 31 for member 25 is also bolted to the motor casing, having an arcuate cam slot 32 therein through which the pin 26 extends, and in which it moves when the operating member 25 is turned to the right or left for the purpose of moving the brushes. The slot 29 in the operating member 25 permits of free longitudinalmovementof the latter when pin 26 moves in cam slot 32.

The power end of the brush operating member 25 is also provided with adjustable abut mentor stop elements 33 and 33a, in the present instance shown as screw bolts res ectively mounted in lugs 34, which are xed in position by lock nuts 35, and adapted to abut against the motor casing extensions 36, or other suitable means provided for this purpose.

A manually controlled actuating element or rod 37 is pivotally secured to the upper end of the brush operating member 25, and passes through an opening 38 of a detent plate 39, fixed to standard 20, and extends to a convenient point at the front of the knitting machine; a handle or knob 40 being secured to its forward end.

Full fashioned machines are usually operated at two different speeds duringthe production of stockings thereon and accordingly I have provided means to permit the brush operating member 25 to be positioned for continuous operation two predetermined positions only.

These are indicated at I and II in Fig. 1. Therod 37 is provided with an adjustably fixed retaining collar 41 which engageswith the detent plate 39 and is held against the same by the action of a tension spring 42 connected to the lower end of member 25 and to the motor casing extension 36. When the parts are in this position the motor is running at its maximum permissible high speed.

When the retaining collar 41 is disengaged from the detent plate 39 by lifting the handle 40, the spring 42 moves the member 25 to position II, which properl sets the brushes for the maximum low spee permissible.

The points of brush setting for the proper motor speeds are thus determined by the ad- ]ustable abutment bolts 33 and 33a and the retaining collar 41. The latter is provided with a set screw so that it may be positioned in accordance with the setting of the abutment bolt 33a.

From this it will be apparent that owing to the action of spring 42, the brush operating member 25 will be automatically moved to the slow speed position II if an attempt is made to operate at a speed requiring the settin of the member intermediate of positions fand II; and that the brushes are therefore, normally retainable for continuous o poration in the proper positions for rimssible maximum and minimum speeds 0 motor operation only.

To prevent an unauthorized person from changing the selected speeds by adjusting the bolts 33 and 33a, I provide a cover 45 which closes the openin in the motor casin through which adwstments are made, an prevent its removal by a cover retaining bolt 47 screwed into the pivot bolt 30, and ordinarily locked in position by a padlock 48, as shown in Fig. 2.

My invention is adapted to work equally well with a variable speed D. C. motor. In this case it is merely necessary to substitute a common speed regulating rheostat for the brush shifting device, as shown in Figs. 6 and 8, and connect it in the motor circuit as well understood. I

Various forms of known rheostat arrangements can be utilized, and therefore the particular one illustrated in Figs. 6 and 8 is to be considered as more or less diagrammatic and suggestive. In these figures the exponent 00 a has been added to parts corres onding with similar elements of Fig. 5. he control lever 25a is directly pivoted at 50 to the plate 31a and ada ted to function as a rheostat lever provide with a properly insulated O6 conducting element 51, functional to bridge a terminal plate 52 and rheostat contact 53, connected with resistance coils as diagrammatically indicated at 54.

It will be apparent that various well known mechanical and electrical expedients may be resorted to in order to adapt the invention to other similar purposes and that therefore, the same is not limited to the precise construction shown and described, butis capable of such changes and alterations as fairly come within the scope of the appended claim considered in connection with the prior art.

I claim:

In a variable speed motor arranged to operate at two speeds onl a swingable control lever normally biased to one position of its speed control, and an operating connection for said lever having manual locking means to retain said control lever at the other position of its speed control a ainst its normal tendency to return to sai first named position.

In testimony whereof I afiix m s1 ature.

MELCHIOR ZV I KY. 

